There is used a slitter line in which a long and wide sheet-like metal plate is cut continuously into a plurality of strips along a longitudinal direction to be made into wound multiple strips at the same time. The metal plate is cut into a predetermined width depending on an application of a metal coil. And, in some cases, more than ten strips may be produced from one sheet of the plate.
In a slitter line, a metal plate is subjected to slitting and formed into multiple strips and, thereafter, the strips are wound by a winder. In this instance, a winding-tension imparting device installed before the winder imparts a winding tension to the strips so that the strips are tightly and securely wound, around a winding coil.
On the slitter line, there is disposed a member which is called a separator for preventing a strip cut to a desired width from being in contact with an adjacent strip. The separator prevents a strip from being in contact with a strip adjacent thereto flowing on the slitter line, thereby contributing to stable threading of strips. The separator also prevents a strip edge from being damaged or bent, thereby playing a role of maintaining the quality of the strips after processing.
The separator is constituted with a plurality of movable disks, each of which is formed by integrating a cylindrical holder with an approximately doughnut-shaped separator disk and fixed on an outer circumference surface of a shaft having a certain length. A strip flows between the fixed movable disks, by which side surfaces of mutually adjacent strips do not come into contact with each other.
That is, when the separator is used, a distance between adjacent separator disks is set in accordance with the width of a strip. Although there exists a variety of fixed structures for a movable disk, in recent years, an air shaft method has been mainly used in which an outer circumference of a shaft is allowed to expand and contract, thereby fixing the movable disk.
Further, the holder plays a role in fixing the separator disk to the center of a shaft at a right angle and a role in preventing the bottom of a strip from being directly in contact with the shaft. The separator disk is a member which plays a role of a partition wall for strips to be threaded.
The separator is disposed, for example, at (after) a rise of a loop, before and after a winding-tension imparting device and before a recoiler in a slitter line. The separator partitions adjacent strips at these positions, thereby contributing to stable threading of the strips. The loop is a portion which absorbs sagging of a strip arising from the thickness of the strip. Further, the winding-tension imparting device is a device for imparting tension when strips are wound in a coil form by using the recoiler.
In the slitter line, there is also installed a cutter stand which has a slitter (cutter portion) for cutting a sheet-like metal plate into a metal strip with a predetermined width. The slitter is provided with a shaft having a blade which holds the metal plate from upper and lower sides, thereby cutting the plate into a metal strip.
The slitter to be used is structured so that a plurality of movable members, each of which is formed by integrating a cylindrical holder with an approximately doughnut-shaped round blade, as with the above-described movable disk, are fixed to a shaft with a certain length. There is also another slitter which is structured so that a member which is called a spacer is inserted between mutually adjacent round blades, thereby positioning the round blades.
A structure which fixes a blade to a shaft of a slitter is available in a variety of types. There is a hydraulic expansion/contraction shaft which allows an outer circumference of the shaft to expand and contract by hydraulic pressure, thereby fixing a holder and a round blade. Further, in the above-described structure in which the blade is positioned by using the spacer, such a structure is adopted in which an inner circumference of the spacer and that of the blade are made substantially equal to an outer circumference of a shaft, by which the spacer and the blade are inserted outside the shaft.
Here, in a slitter line, a strip to be processed is changed in width from several centimeters to more than one meter, depending on an application. That is, during one-day operation in the slitter line, it is necessary to process multiple types of strips different in width.
Where a strip to be processed is changed in width, the separator requires a change in the position of the movable disk according to the width of a corresponding strip. Also, in the slitter which is structured so as to fix a blade by using a hydraulic expansion/contraction shaft, it is necessary to change a position of the blade on the shaft. Further, in the slitter which is structured so as to use a spacer and a blade, it is necessary to perform additional work for removing the spacer and the blade from a shaft to attach a new combination of them.
In this instance, a plurality of movable disks and blades are disposed at equal intervals in accordance with the width of a strip. Work for disposing a movable disk and a blade on the shaft and work for pushing in and out a spacer and a blade were conducted manually in the past. Thus, frequent change in width of a strip seriously affected the efficiency of processing in a slitter line.
Under these circumstances, there is available a disposing device which is capable of automatically pushing a spacer and a blade in and out a shaft (shaft body) of a slitter. There has been proposed, for example, a device disclosed in Patent Literature 1.
As shown in FIG. 10, a device 100 disclosed in Patent Literature 1 is a device which disposes a blade 102 and a spacer 103 so as to be automatically pushed in and out a shaft 101 via a disposing device 104.
The disposing device 104 is constituted so as to move in parallel with the shaft 101 along a guide rail (not shown in the drawing). Further, the disposing device 104 is structured so that a lifting/lowering member 107 and a pusher 108 (pressing member) can expand and contract between the shaft 101 and the guide rail via a cylinder 105 and a piston 106. The disposing device 104 and the lifting/lowering member 107 are restricted respectively for horizontal movement and perpendicular movement by a servomotor (not shown in the drawing) and the cylinder 105.
Here, Patent Literature 1 has adopted the above-described structure in which an inner circumference of the spacer and that of the blade are made substantially equal to an outer circumference of the shaft, by which they are inserted outside the shaft, with a dimensional difference between them being about a few dozen micrometers.
Therefore, when the blade 102 is inserted outside the shaft 101, a clearance 109 develops, as shown in FIG. 11. Although an actual clearance found in the shaft to be used by the device 100 is about a few dozen micrometers, the clearance 109 is depicted in an enlarged manner for clearly showing its presence in FIG. 11.
Due to the presence of the clearance 109, when the pusher 108 allows the blade 102 to move by pushing a side surface thereof, such a problem has been posed that the blade 102 will get caught on the shaft 101 during movement and will not move any more.
Further, it is actually impossible that the pusher 108 pushes a side surface of the blade 102 with an even force at all plural sites every time when the pusher 108 comes into contact, thereby preventing the blade from getting caught on the shaft 101.
Thus, it has been estimated that in the device 100 disclosed in Patent Literature 1, loads of the blade 102 concentrate at an apex of an outer diameter part of the shaft 101 (the position of a load point O in FIG. 11) due to a difference in curvature between the shaft 101 and the blade 102. Then, it has been estimated that where the clearance 109 is present, the blade 102 sways more easily in a back and forth direction and in a lateral direction at the center of a load acting line S which passes through the load point O in the same direction as that at which its own weight acts and also at the center of a line S′ which is orthogonal thereto at the load point O.
On the basis of the above-described estimation, in the device 100, as shown in FIG. 12 (a) and FIG. 12 (b), contact members 110 installed on the pusher 108 push the blade 102 in a state of point contact with a plurality of points on both sides of the load acting line S, thereby suppressing sway in the lateral direction, making the load point O as a fulcrum.
Further, in the device 100, a vertical position at a contact point is selected appropriately so that rotation moment around the contact point is made zero, thus making it possible to suppress the sway in the back and forth direction at the center of the load point O.
More specifically, as shown in FIG. 12 (a), a contact position at which the contact member 110 is in contact with blade 102 is placed within a range equal to ±0.3 times the diameter D of the shaft 101 on the side of an axis line C of the shaft 101 (refer to FIG. 10). That is, in the device 100, the blade 102 is pushed in a point-contact state in the horizontal direction at a site in the depth of ±0.3D in the Y direction in relation to the load point O.
As a result, in the device 100, moment which will sway the blade 102 in the back and forth direction is offset at the center of the contact point of the contact member 110 (that is, rotation moment at the contact point is made zero), thus making it possible to prevent the blade 102 from swaying in the back and forth direction.
According to the above-described constitution, the device 100 allows the blade 102 and the spacer 103 to move smoothly in a direction parallel to the axis line C of the shaft 101 (refer to FIG. 10).
Further, in addition to the device disclosed in Patent Literature 1, there is a disposing device which is capable of automatically disposing a movable disk at a predetermined position by a separator structured to fix the movable disk by an air shaft method.
As for the shaft and the movable disk which are handled by the disposing device, since the shaft is designed to expand and contract freely, an inner circumference of the movable disk (the holder and the separator disk) to be fitted thereinto is formed larger by 10 to 20% than an outer circumference of the shaft.
Therefore, when the movable disk is pushed for movement, the movable disk will easily get caught on the shaft due to a clearance between them. Thus, in the disposing device, a side surface of the separator disk which constitutes the movable disk is in surface contact with two points on the side surface thereof at a height position substantially at the center in a perpendicular direction (the positions indicated by the reference symbol 112 in FIG. 12 (a)).
That is, where the blade 102 shown in FIG. 12 (a) is supposed to be “a separator disk” of the movable disk, a contact portion of the disposing device is to push the positions indicated by the reference symbol 112. In this disposing device, the positions of the reference symbol 112 are each regarded as a position of the center of gravity on the movable disk, and the position of the center of gravity is pushed, thereby suppressing backlash on movement.